In aerospace design it is desirable to seal any gaps between components of flight surfaces to present a smooth surface to the passing airflow. This reduces losses and prevents undesirable fluid flow effects such as separation of the boundary layer and subsequent loss of lift, and prevents leakage over the pressure differential between the upper and lower surfaces of aerofoils.
Components of aircraft flight surfaces such as wings, tail planes, fins, landing gear doors and control surfaces (e.g. flaps, slats, rudders, ailerons and spoliers) tend to move in use both intentionally in response to a control input (in the case of control surfaces) and unintentionally due to thermal expansion and contraction and stresses experienced in use.
As such, the width of the gaps to be sealed between components varies depending on the relative position of the components. Known seal technology utilises resilient seals which are mounted to a first component to seal against a second adjacent component and resiliently deform to the seal gap as it varies.
Such gap width variation is observed between variable camber flaps at the trailing edge of aircraft wings. The gap width between the wing and the flap not only changes due to control input, but also changes as the wing and flap thermally expand and contract with variations in operating temperature and during the flight cycle during which a range of stresses are experienced.
A λ or V shaped seal has been proposed in which the flap is received within the legs of the λ or V. A problem with this type of seal is that the individual legs flex independently and as such can spread and deform with little inherent structural stiffness. Consequently phenomena such as seal flutter can be observed in which one of the legs of the seal is detached (i.e. separated or divorced) from the flap underside.
It is an aim of the present invention to provide an improved flight surface seal.